Telephone party-line switching apparatus.



A.. ..T. FARMER. mzmfwm .PARTY LINE APPARATUS.

.PPLIUATIOH FILED APRS, 1905.

Patmm A931227, 1909.

3 SHEETS-SHEET l.

enferma? Y ARTHUR J. FARMER, Ol" DETROIT, MICHIGAN.

TELEPHONE PARTY-LINE SWITCHING APPARATUS.

Specification of Letters Patent.

Patented April 27, 19091 Original application filed December 26, 1903, Serial No. 186,538. Divided and this application filed April 19, 1905. Serial No. 256,428.

,To all ur/L'ofm. it 'may con cerny.' E

Be it known that I, An'ruun J. FARMER, a

citizen of the United States of America, and

a resident of Detroit, in the county of 'lVayne and State of ,Michigam have indesired station, for eii'ecting the proper sequence of signals at the exchange, and thereafter automatically restoring the selective apparatus to normal or initial position, and otherwise simplifying and rendering more eifective, the connection, selection and rcstoration of telephone lines of this class.

AThe selective feature of my system I obtain principally, by intel-posing between the centratoice and the several parties served a given exchange line, an appliance which I shall term a junction box, the same `containing lswitching mechanism for connecting in circuit all of the stations upon theline, or associated therewith, or merely a given station or group of stations out of the entire number. The actuation and rcstoration of the junction-box.apparatus are `controlled by the exchange-operator through a key or, switch appliance controlling the sources of. current in a common battery ex- "change system; or the restoration may be automatically accomplished by introducing int'o the cord-circuit. suitable apparatus controlled by the called subscribers switch-hook. In selecting a party current preferably is transmitted to the junctionbox over both sidesof the line to ground; while for ct'- fccting its restoration, but one si'de is used, the appliance includingndeans for checking it in. its normal position for calling or receiviiig a call from any of the parties. To meet the added functions, the central-oflice apparatus is modified slightly, including `tllcreinvrelay-mechanism and a source ot current, preferably pulsating, automatically `connected in circuit with the junction-box apparatus when the line requires restoration to normal condition.

My inyention, however, will be more forni of switching-contacts with a portion J ol the contact-nmking drum employed therein; and Figs. 4 and 5 respectively show in diagram ten subscribers7 circuits associated with the junction-box and its metallic-circuit exchange-line; and the modified central-bilico lapparatus so 'far as it. pertains to thc calling side of the cord circuit;--t.hc multiple jacks being duplicated in the two figures. better to indicate the rclation of these diagrams.

The same character of reference is cmployed throughout the drawings to indicate similar parts, or diagrammatic representa tions thereof'.

Having given above, a general statement as to the system of my invention, the details oi its embodiment described therein, will be more readily grasped, by first setting forth thc structure of the junction-box shown in Figs. l to 3. I-have chosen to base my description on the assumption that ten parties, connected two by two, are to be served by a given exchange-line, and accordingly, live sets of contact-making springs l, l to 5, 5"

are provided in the junction box, cach of which is adapted to control one limb of its party-line. An `additional set of contactsprings a is utilized for governing the circuit through th'e actuating` electro-magnet m. Fig. Il illustrates the. preferred form ol" springs used herein` with` the exception merely. of the set c, which requires normallyopcn. or back-contact-making springs as' indicated in Fig. Q.; 'L'. e. in the noruial, or initial position of' the junction-box. 'llhus set l, for example, is seen to comprise two relatively-long, fiexible, springs mounted on the insulating basrI ot' the device; the inner one of which is crimped, or provided with a. projection or elevation, adapted to be engaged by the pins o on the drum .9, to flex said springs and effecta rubbing contact sliding, or relatively movable contact-parts. Mounted on a common shaft t before these setsof contact-making springs, are `the controlling pin-bearing disks f and 1m, 1 to 5T,

, arranged in pairs, but each controlling its own set of springs. F our projecting pins, diametrically disposed in varying rei lation, are borne by ea ch of the paired disks;

those upon the pairs iieiiig identical, so that when thecontrolling drum s, formed'of said disks, is in any other than normal'position,

but two sets of springs, corresponding to the two paired disks, are closed togethenv Thus -springs 3' and 3b, respectively lenga'f'gedby the pins in disks 3 and 3, are shown iexed into engagement to connect the corresponding line-conductors with the exchange. In

the initial position, or positions, however,

vin the junction-box controlling the party lines. At the outer end of theshaft t is mounted the ratchet wheel r, operated through pawl p, by the pivoted armature of the elec-- tro-magnet m. The teeth upon said wheel indicate and correspond to the several opera-' tive positions of the controlling-drum. In

the preferred type of apparatus, one step of the ratchet wheel is designed to open one pair of contacts and close the adjacent pair, or, assuming the drum to be in the initial position, it will break contact between all pairs of springs excepting only springs la andv l", which will be momentarily separated.

andA then immediately brought into contact again. lf springs 5a and 5b be engaged by corresponding pins 0, instead," their contact will be broken momentarily, and then, conlcurrently with a step of the ratchet, contact will be re'e'stablish'ed between springs 5a and 5b as well as between all the other sets of springs, excepting e, which are opened.

This places thejunction-box iii its normal v with the foregoing description, set forth or initial position. Since there are five separate pairs of contact-springs to be actuated, and one initial position is requisite, the drum must be rotatable into'sixvoperative positions. The range of movement of the armature, however, is relatively small, and accordingly, l have grouped Aall six podruni by arranging the sets ofpins to form thc successive contacts between the springs,

' several operative positionseach ot' the pairs ot' springs 1, lb, and 2il and fb, are connected together, and soon. Thus, in all butthe initial positions, Atwo of the sets or pairs of springs are alternatively vsitions upon the seiiii-circumference of the actuated into contact to close circuit, withtlieir respective line-conductors, in common with theclosure of the circuit to the magnet m through the springs e. p

The-ratchet-wheel of the device, necessarily is provided with' twelve equi-distant teeth, representing the twelve operative positions of the drum. It is perfectly obvious, however, vthat by alternating merely' the ratchet wheel and adjustable pin-bearing disks to, suit existing conditions, derent numbers of lines maybe accommodated by the junction-box; and for this reason, the drinn isbuilt up of disks whoseicontaetmaking pins, or operative positions, may be changed as rcquiredf I inay'state, vhowever, that the arrangementdescribed, einploying duplicating contact-making pinsy upon each disk to avoid completely rotating the druin each time a station is selectively called, is' the one to' be preferred. A backstop' pin 6 mounted on the standard 7,

serves to determine the play or movement of thepawl p, by reason of its engagement with the projection 8 thereon.; thus checking the movement of the pawl, armature and ratchetwheel each time in their proper positions.

One of the pair of contacts 10 vis securedvto -thc base portion of the device, whilethe other is carried by the armature; the-.saine being so positioned that they are in eiigagenient with each other only during the re ciprocatioii of said'ari-nature-underthe influence of magnet m. An iiiclosed relay 9,y whose windings ,are connected `with one 'of the line-conductors, is disposed upon the base acont to the actuating magnet. Further mechanical details of the junction-,box ap'- pai-atus, comprise a degli bearing against the Aratchet-wheel and springs` 12, 13 acting respectively upon the pawl and armature',

while a back-stop`14 serves as a -iest for the l arinaturewhen retracted by the spring. 'llie figures ot the drawing, in connection very plainly how the corresponding contactniaking and breaking pins, insulated in their respective disks, effect the .opening of the circuit betweeiisprings e, and the closurefof circuit between the paired sets of spriii s" in turn, when rotated into engagement Wit the projecting portions oftheirv respectivel springs. I 1

Having gained an adequate idea of the inci-hanisni for effecting the several 'circuit :changes within the junction'box,Areterence tothe remaining figurcsof the'drawing'wjll make clear the relation ot' the severa-l parts and their cooperation in the system ot' my invention.

Fig. 4 will be recognized as a diagrammatic representation of ten telephone stations 1, l, to 5 0, 5d, connected with the lineconductors 15, 16, extending to the exchange through the medium of,the j unction-bo'x apincluding battery 28h and contacts 20; provision heilig 'made for the closure of another circuit through the same whenever contacts 24 and E29 are simultaneously closed-or when they are closed during the same period. Since. the restoring current ,from source 27h is to be sent. to line only when the lug is inserted in the jack and the subscri er hangs up his receiver, it becomes necessary to provide such an arrangement of circuits and relays that a circuit will he partially completed when the subscriber takes down his receiver, and electrically closed upon his hanging up the same. Woreover, the relay apparatus associated with the. cord circuit, vmust be restored. to normal condition upon the removal `of the plug from its jack.

.For thepnrpos of illustrating the worklings oli-my invention, let us assume that the operator has received-ay call tor subscriber 3, and trace out the various steps or circuitehanges necessary to secure his connection lin circuit, and the return ot' the apparatus answer, however, ltey t8 would be pressed three times more by the operaton` and the plug would be rcnn'ived trom the )aek. lVe

- will follow the operation, assuming that subscriber I3 ai'iswers his call. Upon plugging in. current flows from grounded battery Q2 through relay to lamp 23, ring aml thimble otl the plug and jack` relay 'v and to `round thereby insuring the closure of contacts Qt while the plug remains in the jack. Supervisory-relay 'Le is energized upon they subscriber answering his call and removing the receiver from its hook, by reason ol the lowresistance bridge across the line; hence contacts 2l are. opened and contacts 2() re- 'main closed while subscriber .f is talking. The latter contacts complete an independent `circuit including battery QS, through the windings ot' relay and its` contacts .t and 9!) are actuated into engagement. Contact. 26, it will be seen, is one oll the controllii'ig contacts in the grounded circuitv including rthe source ol ,intermittent current 2'7" and magnet m, i'or etfecting ,automatic restoration. The closure of contacts 2f) otl relay e', during the engagement of contacts 24 of relayfc, completes a separate circuit from battery 28hthrough relay z, so that the latter will .remain energized while the plug is in the jack. When subscriber 3" hangs up his receiver', the supervisory relay is at once deencrgized, thus openingr contacts 19 and 20 and closing contacts 2l. The latter closes the circuit; already partially established, lroni the source ol intermittent currentI 27D, through contacts 2G and 2l, the key-coi'itacts and those ol the plug and jack to line-conductor 15, thence to manget m," where the current impulses serve to step the junctionbox apparatus into initial position, whereupon tbc 4circuit. to magnet m is broken in the manner betore described, and the apparatus remains at rest. While thisis occurring the intermittent current. is tlowing through the windings of relay y, so that its contacts 2T are alternately closed and opened, and contacts '2S simultaneously opened and closed; the one shunting the supervisorylamp, and the other opening the cord circuit to the answering side, to prevent any restoring current `t'rom reaching that side of the. connection.' Supervisory-lamp 23, now normally lighted, is alternatelyy extingr'iished and relightcd, by reason of 4the intermittent shunt, until the junction-box.apparatus is completelyrestored; thus serving to warn the'operator not to take down the connection until the. lamplnn'ns steadily as a proper signal therefor. Removing the plug upon getting the said signal, of course, restores the exchange-a pparatus to normal condition, and, as explained, the several stations connected with the junction-box apparatus, are left bridged acrossl the main lineA conductors, so that any one can signal the Aexel'iange in the well known manner.

In the foregoing, I have clearly set forth, l believe, the most desirable application of .my invention, but l may merely allude to other advisable en'iployments thereof. For example, the number of contact-springs in ythe junction-box, and theicorresponding operative positions, are readily and very simply altered to meetexisting requirements, by adding or removing the springs and changing the contactlmaking disks upon the drum. The connection `otl the junction-box with the subscribers circuits,

likewise i's subject to numerous alterations to meet. varying coi'ulitions.' Thus, although practical privacy in the use ol.t the lille is obtained in the example. given, since all'thc parties but` one aredisconnected during conversation, and a selective signal is provided for, live parties may he given service in absolute privacy and over individual metallic lines, -using the same apparatus; the contact-springs then controlling both limbs ot' the line. Twenty, or any intermediate number of, parties, might., on the 'other hand` he connected to the apparatus tor service should it be desired; selective calling being provided it'or simplyby adopting the well known polarized bells and corresponding means for ringing them. However, these, and other modifications will be plain to those skilled in the art, and

pliance previously considered. The use of the saine characters` of reference in the drawings shall render the diagram largely selfexplaiiatory.' It will be observed that each station is connected with one or the other of the line conductors in a permanent manner, while connection with the otheror opposite line conductor, is controlled by an individual spring within the junction-box. For example, line conductor 15 is continuous to station l"I` in common with four other stations, hut the circuit to said stat-ion, via conductor to, is controlled entirely by the paired contact springs la within the'junction-box.` On

the other hand, station la ia permanentlyl connected with line conductor lt, wltile springs lI govern the return circuit over line-conductor l5. l have already explained, however, that under the circumstances of use assumed, a eet or group of springs (coinprising' two pairs ot' springs, as la, l",) is simultaneously actuated into and out of engagement; hence stations le, ld, iiiiist together be connected in multiple with and disconnected troni the line-conductors. he

' signaline-bells b at the several Stations are f D t respectively connected between one or the other ot' thel line-conductors and @round through the usual condeneers c, so that the operator can, in the simplest manner possible, selectively call the desired station when its group ot two is connected in circuit; such connection necessarily being;` coupled witli the disconnection ot all the other grt'aipt, except in the initial or normal position ol the apparatus. lt is: important. to observe that in each caset'he ringing eide ot' the stationline is the controlled limbot the circuit. lelay t), in the particular arrangement shown, is permanently connected between conductor lo and lLround'. while the actuating' electro-unione( nt is associated with liucconductor l5 through thc inediuni olI any oln the uuiltiple-contacta c. l() or 1T: the l'u-.st being' the controllable contact-springs within the junction-box. the lsecond the auxiliary contacts directly actuated by the a rniature.A and the third the contacts ot relay t). All ot' theee are initially or normally separated. 'lhe characteristicsv ol' the junction-box apparatus, accordingly, are. seen to be such that the operator may. by directing current over hotli line-conductors in pnrallelfwlith ground return` Step the contact-controlling drinn trom the initial position into any ot' the live operative positions wherein the stations are connected to lino two by two,itor the purpose ot selective signaling; whercae, to return the iiniction-bof apparatus to the initial position, current is directed over lineconductor 15 only. ll'aving' given attention to thet'oregoing, the reason t'or this will be f apparent.

ln the initial position contactsprings c are separated, so thatiio current can rent-,lr n'iagnet m until the relay contacts 17 are closed. However, immediately the controlling drum is advanced from its initial ,poeitioin circuit.' through the magnet m is established between contacts e, and the drum may be advanced through its several positions until initial position is again reached, t

'the armature,l and .serve to afford an independent path for the current actuating the magnet, and avoid the premature opening of the circuit hy reason ot the separation of springs c. lt will be. understoodthat the several windings connected between the lineconductors and Around are ot' such high iinpedance as to preclude the formation of a low resistance bridge acrose the metallic lineconduct'ors.

.t number ot' inoditicatione of the Stand-A is enabled to accomplish the results already.

alluded to, in' that She can after selectively signaling any station return the junctionbox apparatus to the normal or initial position manually, or. the saine may he don automatically upon the subscriber`s hanging up his receiver. For selectinc a party and subsequent manual restoration. ltey 1S is presaed the requisitiA number ot times to select a pair o t stations. one ot' which is then rune by means ot hey l() or Zit. and when return to the initial position is desired, switch $52 is opened and the Jsanie key 18 is again 'pressed the number ot' times necessary to restore the junction-box apparatus. xSwitch 252 is provided tor the purposev ot .sendingl current orer one or both ot the lineuonductors by way oi ltey t8,v and may be opened when inanual restoration is resorted to. tor preventing' thtw-ontrolling drum from beine actuated past the initial position. 'l will ,-et t'ortli, however. the pret'erred inode ot' effet-.ting the re.-ztoration ot the junctionbox al'iparatuts and automatically connecting all of the party-linesl in circuit. lt\jwill first be observed that the supervisory-rela-yfw, in

addition to the usual contact 1li) toreeontrolling' the signal-lamp,- iS equipped with *the 'contacts '30 and Q1 for effect-ing a special., Ypurpose. battery is provided a relay .1'. whose 'con ln circuit with the lan'ip Q?) and tacts Q4 interniediately control a Special circuit. lncluded in circuit with the cord 25, are the relay -,1/. contacts 2l, Q6, and leource ot intermittent current 2T". Contacts QS'ot the latter relay serve to open and close` the answering-Side ot the cord-circuit. while the contactsl 2T areprovided t'or the control of a .shunt about the siipervisory-lamp 23.1

other relay z, is connected in a. local circuit ltltl ilio.

I claim the following as setting forth my invention l. In a switching appliance of the class described, the combination with the controlling electro-magnet and its armature, of a relay device governing the lcircuit therethrough, andin multiple with its actuated contact, a normally open, self-controlled contact, and a contact closed only during the movement of the armature, substantially as set forth.

2. In a switching appliance of the class described, the combination with a rotatable element and electro-magnetic means for effecting its actuation, of a plurality of actuated'but stationarily mounted springs for et'- fecling the control of the party line circuits, and a pair alternative to all of the other springs, and normally open for controlling the electro-magnetic means substantially as set forth.

. 3. In va party-line switching appliance, the combination with a rotatable element andelectromagnetic means for actuating the same, poi" a plurality'of stationarily mounted pairs of contacts pr springs for effecting the circuit changes, one pair being alternative to all ot' the others and n'r, mally open for governing the electro-magnetic means, all associated with said element and actuated thereby, and a relay device governing contacts in multiple with the latter, substantially as set forth.

4. In a switching mechanism of the class described, the combination with an electromagnet and its armature, of circuit-controllingY er switching contacts, associated parts -t'or el'l'ecting the actuation thereol by the movement of the armature, and an auxiliary contact controlling the circuit through the magnet, the same being normally open but adapted to be closed during the movement of the armature substantially as set forth.

ln a switching appliance of the class described, the combination `with an actuating electro-magnet and its armature, of circuit-controlling or switch-ing contacts, associatedmechanism for effecting the actuation thereof by the movement of the armature, paired governing contacts, and auxiliary contacts jointly controlling the circuit through the magnet; the latter being in multiple with the other contacts and normally maintained open, but adapted to be closed during the movement of the armature, substantially as set forth.

Signed at Detroit, Michigan, this 27th day of March, 1905.

ARTHUR J. FARMER.. lVitnesses: 4

S. E. THOMAS, ALLAN MCLERIE. 

